#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
int a[100100], b[100100];

int main() {
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	for (int i = 1; i <= m; i++) {
		cin >> b[i];
	}
	sort(a + 1, a + n + 1);
	int ans = 0;
	for (int i = 1; i <= m; i++) {
		int l = 0, r = n + 1;
		while (l < r) {
			int mid = (l + r) / 2;
			if (a[mid] <= b[i]) {
				l = mid + 1;
			} else {
				r = mid;
			}
		}
		if (b[i] <= a[1]) {
			ans += a[1] - b[i];
		} else {
			ans += min(abs(a[l - 1] - b[i]), abs(a[l] - b[i]));
		}
	}
	cout << ans;
	return 0;
}